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7.9 Port 9
7.9.1 Overview
Port 9 is a 6-bit input/output port that is also used for input and output (TxD
0
, TxD
1
, RxD
0
, RxD
1
,
SCK
0
, SCK
1
) by serial communication interface channels 0 and 1 (SCI0 and SCI1), and for
IRQ
5
and
IRQ
4
input.
Port 9 has the same set of pin functions in all operating modes. Figure 7-21 shows the pin
configuration of port 9.
Pins in port 9 can drive one TTL load and a 30-pF capacitive load. They can also drive a
Darlington transistor pair.
Port 9
P9 (input/output)/SCK
P9 (input/output)/SCK
P9 (input/output)/RxD (input)
P9 (input/output)/RxD (input)
P9 (input/output)/TxD (output)
P9 (input/output)/TxD (output)
5
4
3
2
1
0
Port 9 pins
1
0
(input/output)/IRQ (input)
(input/output)/IRQ (input)
5
4
1
0
1
0
Figure 7-21 Port 9 Pin Configuration
7.9.2 Register Descriptions
Table 7-13 summarizes the registers of port 9.
Table 7-13 Port 9 Registers
Address
*
Name
Abbreviation
R/W
Initial Value
H'FFD0
Port 9 data direction register
P9DDR
W
H'C0
H'FFD2
Port 9 data register
P9DR
R/W
H'C0
Note:
*
Lower 16 bits of the address.